The present invention relates to a method of making a window glass with a gasket suitable for automobiles and buildings. More particularly, the present invention relates to a method of making a window glass having a curved portion and provided with a gasket.
It has been known to attach a gasket, a molding or a frame member (hereinbelow, referred to simply as a gasket) made of a material of rubber or a synthetic resin for the purpose of decorative trim strip or a seal at a peripheral portion of a window glass for an automobile or a building. More specifically, a gasket 2 is attached to the peripheral portion of a window glass 1 as shown in FIGS. 3 and 4.
In order to attach the gasket to the window glass, it has been known to use a method in which a gasket prepared by an extruding method is attached or fitted to the peripheral portion of a window glass. However, this method has problems that wrinkles are resulted at a corner portion or it is difficult to attach the gasket to the window glass when the window glass has a complicated shape because the gasket is formed in a linear form and the linear gasket has to be bent along a curved portion of the window glass.
In order to solve the above-mentioned problems, there has been proposed a method of making a window glass with a gasket in such a manner that a window glass is disposed in molding dies, a gasket material such as a plastic, rubber or an elastomer in a molten state or a mixture of raw materials capable of forming a plastic, rubber or an elastomer is injected into the molding dies to fill the material in a cavity formed at the peripheral portion of the window glass received in the molding dies, and thereafter, the window glass with a gasket is removed from the dies. Such method is disclosed, for instance, in Japanese Unexamined Patent Publication Nos. 158481/1982, 73681/1983, 110786/1983, 4015/1985, 104412/1985, 63115/1985, 79613/1986 and 66645/1986.
In accordance with the above-mentioned method, the window glass is put in the molding dies having an upper mold member and a lower mold member. A gasket material is injected in a cavity formed around the peripheral portion of the window glass enclosed in the molding dies. When the gasket material is solidified in the dies, the molded frame member is removed from the dies together with the window glass. This method will be described in more detail with reference to drawings.
As shown in FIG. 1a, a window glass 1 is arranged in a mold 5 comprising a first mold section 3 and a second mold section 4 so that the window glass 1 is held by the first and second mold sections 3, 4 to thereby form an inner cavity 6 at the peripheral portion of the window glass 1 (FIG. 1b). A gasket material such as a plastic, rubber or an elastomer which is in liquid state, a molten state or a mixture of raw material capable of forming a plastic, rubber or an elastomer is injected into the inner cavity 6 through a gate in mold portion 7. Thus, a gasket 2 is formed by the solidification of the gasket material in the inner cavity 6. Then, the window glass 1 attached with the gasket 2 is removed from the mold 5 by separating first and second mold sections 3, 4 as shown in FIG. 1c.
In the above-mentioned method, it is necessary to strongly clamp the window glass 1 by the first and second mold sections 3, 4 when the window glass 1 is held in the mold 5. Accordingly, there was a problem that the window glass 1 is apt to be broken due to a clamping force. This problem was particularly critical when a curved window glass 1 was to be handled. Namely, it is difficult to increase accuracy in the bending of the window glass 1, and it is unavoidable that there is dispersion in the dimensions of a curved window glass. Therefore, when the window glass 1 is clamped between the first and second mold sections 3, 4, a stress is applied to the window glass 1 to thereby cause the breakage of it. Recent years, a window glass having a sharply bent angle or having a complicated shape has been used for an automobile. The window glass having a curved portion is apt to be broken. Further, when broken, an economical loss is large. This is a reason why the above-mentioned method has not been applied. When a previously prepared gasket is fitted to a window glass having a curved portion, it is difficult to fit the both members because the shape of the gasket does not often meet with that of the window glass.